I would tend to agree with Chris.
The number of times that I have turned up to a job, only to find, it's in a really difficult(1960's) house, and the people want all of the wires hidden, where you have to double the number of lights and socket-outlets, even with no ceiling void and a switch-board that is so over-crowded, there's no room left for mice, let alone an extra MCB.
If you come out of the other side of a job like this, with your Quote and your Mental sanity intact, I think that you qualify for the "Electro-Magician" Title.
After all, most home-owners, seem to think that all we do is wave a Magic Wand and it's all done.("should'nt take you long"- as my Boss says). yeah right!.